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The dual clutches are an integral part of a Dual Clutch Transmission, that would be redundantly redundant. (Also they're in parallel, not series as you've shown, but to draw that you'd have to show gearing and shafts, at which point you're just drawing the whole transmission anyway rather than a box representing it as a component.)

Edit to add: Okay, the twin clutches in a DCT could be concentric. Wonder which physical arrangement our cars use?
 

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I think that diagram needs to be updated to include dual clutch between the electric motor and transmission.
something like this:
View attachment 30713
The dual clutch you are talking about is in the DCT Box. It is misleading to separate it out of DCT box as you're drawing because it is part of DCT.
 

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2 things to make clear: 1) the low speed creeping is the electric motor, not the clutch slipping. 2) there really is no point in shifting to N at a stop light because the clutch is not slipping and the engine will shut down.
 

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The dual clutches are an integral part of a Dual Clutch Transmission, that would be redundantly redundant. (Also they're in parallel, not series as you've shown, but to draw that you'd have to show gearing and shafts, at which point you're just drawing the whole transmission anyway rather than a box representing it as a component.)

Edit to add: Okay, the twin clutches in a DCT could be concentric. Wonder which physical arrangement our cars use?
Oh, I did not know that dual clutch is inside the transmission.
that is interesting. Are the clutches of "dry" type, separated from the gears or are they "wet" type sharing the same fluid?
 

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Oh, I did not know that dual clutch is inside the transmission.
that is interesting. Are the clutches of "dry" type, separated from the gears or are they "wet" type sharing the same fluid?
It is dry clutches activated electrically, one for odd gear and another for even gear.
 

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Still haven't figured out where reverse comes in. If I'm not mistaken, it has a different drive ratio than the 6 forward gears.
 

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Yeah, I've wondered about both Reverse and Park. In theory they could each be a cog on a dog clutch the same as the other gears. You'd put Reverse on the even shaft/clutch so it's easy to rock the car between 1 and R for freeing it in winter, and Park on the odd shaft to balance Reverse and make it a smooth sequence from P to R to N to D. Then you'd have four positions / two forks per shaft, with neutral disengaging the input clutches on both shafts. Park would be special as it wouldn't be a gear with a mate on the input shaft, the dog clutch would just engage a fixed gear or piece.

Of course what Hyundai actually did is anybody's guess (unless it's in that service manual PDF that I haven't gotten around to downloading yet). Reverse could just be 1st gear with the electric motor spinning backwards, while Park could just be 1st gear and the hybrid clutch coupling the motor to the ICE and relying on engine compression for resistance (like many folks do with a traditional manual). Even more exotic, Park could be engaging 1st from the odd shaft/clutch and 6th from the even shaft/clutch at the same time, relying on the mismatched ratios to lock up. That would either be really clever or really foolish, not sure which...
 

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Great videos @Cha !

They all deal with DCT's for ICE-only cars though. If they did a clean-sheet design specifically for hybrids, you could do the whole thing with nothing but 1,3,5 on the odd shaft and 2,4,6 on the even shaft, shifted by just three forks. (The centre fork could select between one gear driven off the odd shaft and another driven off the even shaft.) That would minimize weight, complexity, and size, leaving more room for the electric traction motor.

The rest is software: Reverse could be done entirely with 1st gear and the traction motor running backwards with the ICE disengaged (but possibly running to supplement the traction battery through the hybrid starter/generator), and Park could be done by engaging both an odd shaft gear and an even shaft gear at the same time and letting the thing lock up due to the different ratios (the farther apart the better, like 1st and 6th). To get it out of park you disengage both the odd and even shaft clutches to relieve any lockup pressure, then select and engage just 1st to drive away in forward or reverse as per the driver's selection. Reverse could still reach a higher top speed than 1st normally does because it's electric only, and presumably the traction motor could rev higher than the ICE since the two will never engage while reversing with this design.

That's what I would attempt with a clean sheet design, what Hyundai actually did for the IONIQ I don't know, as there could easily be complications and trade-offs I'm overlooking. Now I'm itching to find out, I really need to get around to downloading that service manual!
 

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That's the one I was planning to snag yeah. I'm still not on the home computer at the moment though, and I don't want to try reading it on my phone... :)
 

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I did some bedtime reading last night, the PHEV/HEV does have a physical reverse gear (I know you had already said that, but now I've seen it from an accredited source so have no choice but to believe, lol):

30751


Unfortunately the DCT chapter doesn't show the guts of the transmission itself, so the mechanics of Park remains a mystery. :-(

Also, I find it odd that the final gear ratio varies by range rather than by odd shaft versus even shaft. I really wish they had shown the guts of this thing in that chapter.
 

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I did some bedtime reading last night, the PHEV/HEV does have a physical reverse gear (I know you had already said that, but now I've seen it from an accredited source so have no choice but to believe, lol):

View attachment 30751

Unfortunately the DCT chapter doesn't show the guts of the transmission itself, so the mechanics of Park remains a mystery. :-(

Also, I find it odd that the final gear ratio varies by range rather than by odd shaft versus even shaft. I really wish they had shown the guts of this thing in that chapter.
that sort of makes sense of an intermittent issue I have with downshift 5th to 4th on a slope which don't occur with any other shift, if it changes the final drive ration (like an overdrive) between 4th and 5th I wonder what the mechanism is, as there is no mention of any additional clutches
 

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I wonder if it's a typo, and if it's really the odd gears shaft that has one final drive ratio while the even gears shaft has another? That could be possible without an additional clutch. (Although the design of a DCT in my head has two input shafts gearing onto a common output shaft, which certainly doesn't jive with having different final ratios.)

I had once bought the 1995 Dodge Avenger Dealer Service Manual from ebay to do some work on my car, and some of the service procedures flat out made no sense as written. I later found out through forums that the 1996 service manual was heavily revised due to all of the 'year 1' errors in '95 manual, despite nothing really having changed on the car. Maybe it's the same with the 2017 HEV documentation versus later years?
 
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